1. Field of the Invention
The invention concerns an arrangement to print strip-like print media in a franking and/or addressing machine.
2. Description of the Prior Art
An arrangement of the aforementioned general type is known (see DE 197 12 077 C1) in which the print media are transported on edge, resting on a guide plate with a printing window, by means of contact pressure elements attached to a revolving transport belt, and the media are printed by an ink printhead located behind the printing window. In the entrance region of the otherwise typical print media, a strip magazine is arranged transversely to the guide plate and at a distance from the guide plate that is greater than the largest permitted thickness of the otherwise typical print media. The strip-like print media—simply strips in the following—are supplied as an output from a magazine transversely to the transport direction and above the transport plane of the transport belt toward the guide plate. For this purpose, the strip magazine is provided with a separate drive formed by a motor, reduction gear and drive roller. A recess is provided in the guide plate in the impact region of the strips, into which recess is inserted a specifically shaped guide part. The middle of the exit opening for the strips from the magazine, the middle of the guide part and the middle of the printing window are all situated at approximately the same level.
As is apparent from the above description, this solution is limited to only a specific, complicated transport system, and the technical design cost is also significant. The output relationships do not allow any reloading during operation.
A modular strip dispenser is known (see DE 202 18 855 U1) that is designed so as to be connectable with a mail processing machine. The strip dispenser has a shaft beam and a removable strip receiver shaft that is adapted in terms of its length to different strip lengths. Integrated into the shaft beam are a take-off unit and sensors that can be electrically connected with a control unit of the mail processing machine. The take-off unit has a stepper motor that can be controlled by software o as to produce a desired take-off speed, corresponding to the different machine variants. A sensor installed in the shaft beam checks whether a strip has been taken off or whether a strip is located in the strip guide. The strip receiver shaft has a mechanical sluice with which the maximum fill level is established. In the output region of the strip receiver shaft, two levers that can be moved against an elastic force are supported between the upper outer wall and the inner wall. The spring-loaded levers extend to the exit opening and press the strips against a take-off roller.
If only one or a few strips is/are isolated, the strips may be pushed too far through, and recurve at a blocking part, and therefore an error mode is triggered (given one strip) or an isolation is impossible (given multiple strips).
In addition to the technical cost for the separate drive for the strip dispenser, the matching between ejection velocity and the transport velocity of the mail processing machine is problematical. Given a difference between these velocities, print offsets can occur in the print image. The maximum offset occurs when the drive in the strip dispenser is deactivated immediately after the isolation. Depending on the geometric dimensions in the region between strip ejection and printing region, for a particular strip length it may occur that a portion of the strip still sticks into the strip dispenser while the front part of that strip is already being printed. It is clear that a reloading during operation is not possible here.
Furthermore, a strip dispenser for mail processing machines is known (see U.S. Pat. No. 6,773,524 B2) that has a strip magazine in which the strips are stacked one after another, resting with their leading edges on a base plate. The mail processing machine has a transport system that has multiple parallel (upper and lower), revolving transport belts actively driven by rollers. The strip magazine has a matching slit located centrally relative to one of the upper transport belts in the outermost region of the forward driven roller. The strip take-off position is centrally established by an electromagnet that pulls the slit of the magazine into the engagement region of this transport belt. If the electromagnet is not fed with current, the magazine remains pivoted away and no strip is taken. The removed strip is initially non-positively taken along by the upper transport belt through the slit between floor plate and transport belt, then strikes with its leading edge on the lower transport belt and is deflected by the lower transport belt and is directed further. In the subsequent printing position, the strip segment located there lies only on the lower transport belt opposite the printheads. A correspondingly designed counter-pressure element might not be necessary.
The strips must be situated at a defined angle relative to the base plate so that they are not excessively curved and safely arrive at the slit to the transport belt. If they are wavy or do not have a smooth cut edge, this can lead to malfunctions. Different flexural strengths of the webs can likewise have a disadvantageous effect. In this solution there is also the risk that, upon insertion of one or a few strips, the strip or strips may already have slid into the output slit, which results in the errors described above. The transport system is complicated and requires a precise matching between the upper and lower transport belts.
In addition, a transport module is cited (see DE 10 2007 060 789 A1) that is arranged above a feed table and (in a known manner) has a transport belt for flat print media. The print media, arriving from the feed table, are pressed against the transport belt by means of elastically arranged, spring-loaded pressure elements (advantageously brush elements) below the transport belt. Due to a number of such contact pressure elements, a correspondingly large contact area is achieved, so start-stop errors in the print image are largely avoided (see FIGS. 2 and 3).
Finally, a transport device for flat goods to be printed is known (see DE 10 2008 032 804 A1) that has a driven, revolving transport belt supported on rollers. A number of spacers that are axially parallel to one another are arranged between one end of a bearing plate of a roller support and a first shaped plate, and a number of spacers axially parallel to one another are likewise arranged between the other end of the bearing plate and a second shaped plate. The spacers are all identical and designed as bearing shafts. Respective tensioning means are mounted at the ends of the bearing plate of the roller support and are designed for force transmission from a connecting rod. For a defined flexing of the roller support with corresponding loading of the bearing plate, a mechanical draw tension is transmitted via the tensioning means to the two ends of the bearing plate. The connecting rod is provided with tensioning and adjustment means to adjust a defined draw tension (see also FIGS. 2 and 3).
The last two cited solutions, matched to one another, form a compact transport device for franking machines with small to medium of mail items throughput; see also Design Patent registration with the Office of Harmonization for the Internal Market, file number 001292361-0001 and FIGS. 1 through 3.